Furnace of steam-boilers and the like.



W. G. UROSTHWAITE. FURNACE OF STEAM BOILERS AND THE LIKE.

APPLICATION FILED SEPT. 27, 1905.

957,310, I Patented May 10,1910.

2 SHEETS-SHEET 1.

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21-- Quinnoz Wihmaaw ANDREW a GRAHAM co FHOTF-UYHDGRAPHERS,WASHINMDN. u,c

W. G. GROSTHWAITE.

' FURNACE OP STEAM BOILERS AND THE LIKE.

APPLICATION FILED SEPT. 27, 1905.

957,31 0. Patented May 10, 1910.

2 SHEETS-SHEET 2.

animator UNITE STATES PTENT WALTER GEORGE CROS'II-IWAITE, OF LEEDS,ENGLAND, ASSIGNOR, BY MESNE ASSIGN- MENTS, IO THE UNITED CIGARETTEMACHINE COMPANY, LIMITED, OF LONDON, ENGLAND, A CORPORATION OF GREATBRITAIN.

FURNACE OF STEAM-BOILERS AND THE LIKE.

To all whom it may concern:

Be it known that I, IVALTER Gnonen Gnosrrrwarrn, a subject of the Kingof Great Britain and Ireland, residing at York Street Mills, Yorkstreet, Leeds, in the county of York, England, have invented new anduseful Improvements in or Relating to the Furnaces of Steam-Boilers andthe Like, of which the following is a speci fication.

This invention relates to improvements in the furnaces of Cornish, orLancashire or other like boilers employed for generating steam.

The invention has for its object a furnace grate constructed in the fineof firebars so as to constitute not only a grate for the fire, but alsoto provide air conduits for conveying forced or natural draft to theburning fuel, and also forced or natural draft to a bridge of specialconstruction for smoke consumption by separate passages all formed inthe bars themselves.

In the drawings hereunto annexed :--Fig ure 1. is a part longitudinalsection of the fine of a boiler with this invention applied. Fig. 2. atransverse section on line 1, 1, Fig. 1. Fig. 3. a transverse section online 2, 2, Fig. 1. Fig. t. a horizontal section on line 3, 3, Fig. 2.Fig. 5. ahorizontal section on line I, 4, Fig. 2. Fig. 0. a horizontalsection on line 0,. 5, Fig. 2. Fig. 7. a horizontal section on line 6,6, Fig. 2. Fig. 8. a horizontal section on line 7, 7, Fig. 2. Fig. 9. adetail view of air tube and grate bars. Figs. 10. and 11 perspectiveviews of opposite sides of a grate bar. Fig. 12. a vertical section offour grate bars arranged as in position.

A is the flue shell or casing of, say, a Lancashire boiler, the firebarsB,-forining the fire grate,arranged transversely within the fine onlongitudinal bearers not shown in the drawings. The firebars Bhereinafter described and illustrated are constructed similar to thosedescribed and illustrated in the specification of United States LettersPatent granted to Thomas 'Westerly and Walter George Crosthwaitereissued May 23, 1905, No. 12,351. The firebars so constructed are shownat Figs. 10 to 12 of the accompanying drawings, and they possess thefollowing essential features.

The firebars B are shown provided with feet C which rest on the bottomof the flue Specification of Letters Patent.

Application filed September 27, 1905.

Patented May 10, 1910.

Serial No. 280,335.

In each bar B are formed holes E which, when the bars are placed side byside in the fine to form the grate, constitute continuous passageslongitudinally of the grate for the air blast. The holes E are closed atthe rear end of the grate by omitting the said holes from the rearmostbar, or by the fire bridge D itself, so as not to deliver air to thebridge. The firebars abut against each other at their surfaces 1), butat 0 they have fan-shaped recesses communicating directly at their lowerends with the upper parts of the air passages E,that is to say, the recesses are made to increase in width from the air passages E to theupper surface of the firebars,-so as to deliver a blast from thepassages E in an upward direction through said recesses 22 in a fanshaped current into the fire, the fiat abutting faces preventing anyescape of air from passages E downward toward the ashpit H. The fanshaped recesses b are inclined or formed wedge shaped vertically. Therecesses 12 are wider at the base than at the top as shown, providingwhen the bars are placed side by side a number of channels K betweencontiguous bars which gradually nar-. row toward the top and finallyterminate in narrow openings L at the surface of the grate. The uprisingair is thus made to enter the channels K at the lower part where thereis comparatively large area, and by reason of the channels graduallycontracting in area toward the narrow openings L, the air passage isrelatively contracted in vol ume which causes the air to rush throughthe openings L with a greatly augmented velocity and this rush of airthrough the bars tends to keep the grate cool.

The air is prevented from leaking out between the bars at their abuttingfaces 0, should said faces be cast not quite true, by the projectingflangesc which partially pro ject around the lower half of the holes Eon one side, and by corresponding annular recesses 6 (also around thelower half of the said holes E which form grooves or seats correspondingto the contour and dimensions of the said flanges e) in the other sideof the bar, so that when the bars are placed togther to form the gratethey interlock at the holes E and leakage of air at their abutting facesis thereby minimized. The blast of air is delivered in a fan shapedcurrent upward through the bars which causes the heat to impinge againstthe top of the furnace portion of the fine and produce a fire of greatheat and uniform intensity. I are separate air passages in the bars andthrough the bridge so arranged as to deliver forced or natural draft atwill into the air chamber 6 (to be presently described) at the bridge.The passages I are shown smaller,but not necessarily so,in size thanholes E, and they may also be provided with rings and annular grooves soas to in terlock in the same manner as the air passages t. J is thesteam jet at the entrance to the air passages for introducing the forceddraft.

No claim is made in this specification to the above described firebars,except when used in combination with a bridge D constructed ashereinafter described.

The bridge D is shown built over a portion of the rear of the bars B,and a portion of the bridge is employed for blocking the holes E so asto prei ent the passage of air therefrom to the chamber 6, or the holesE may be omitted from the rearmost bar. The bridge D is built of bricks,made of fireclay, in a number of layers or courses, hereafter termedcourses. In the drawings five courses lettered O, I, Q, R, S, are shown.In each course one or more air chambers or passages is or are formed andarranged as hereafter described, and they respectively communicate withthe course immediately above it. The course 0, level at its top with thetop of the fire-bars, is shown to consist of more than one (three areshown) layer of bricks, and its front end will be carried on one or morebearers not shown in the drawings. A passage 3 is shown at or near therear of this course, but it may be arranged in any other convenientposition. The passage 3 communicates at one end with passage at whichruns under and beyond the rear end of the grate to the front of the sameand at the other end with the air chamber 6 formed in the second courseP. In the second course P an air chamber (3 is formed at or about thecenter of the course, and it is provided with a longitudinal divisionpiece 7 (see Fig. 5) extending for a portion of the length of thechamber from its end nearest to the front of the bridge rearward. Toeither side of the divisional wall 7 is an air-passage numbered 9 and10, respectively. The outlets 1 and 2 of the passages or air conduits I,I are arranged to communicate with the passages 9 and 10 near the end atthe front portion of the bridge to either side of the division piece 7.Passage 3 is also in communication with the same air chamber 6 at asuitable distance from the rear of the bridge, and by means of thepassage 4, said passages 3 and (3 com municate with the air space orpassage-way under the grate. The third course Q, which may be formed ofone or more slabs or quarries,two are shown at Fig. 6,forms the top orcovering for the said air chamber. In the third course Q a transverseair passage 8 is formed at a suitable distance from the front of thebridge. The passage 8 communicates with the air chamber 6 below, bymeans of air passages 9, 10, of the course P. The passage 8 alsocommunicates with the two air chambers 11, 12, in the fourth course R ateach of its ends by means of the air passages 13 and 14.

The two air chambers 11 and 12 are formed at or about the center of thecourse R (see Fig. 7) and they are divided from each other by means of acentral division piece 15 (see Figs. 1 and 3). The chambers 11, 12, arecovered by the fifth course S (see Fig. 8) which forms the top of thechambers, and they are open to the flue at the rear of the bridge. Thepassage of the air within the bridge-wall is as follows: from passagesI, 1 and 3 into the chamber 6, thence by way of passages 9 and 10,through passages 8, l3, and 1 1 into chambers 11 and 12 and out into theflue and commingles in a warm or heated state with the gases and otherproducts of combustion arising from the consumption of the burning fuelon the fire-bars and passing over the bridge.

The fine shell or casing A may be suitably lined at the crown with anarching of firebrick 16 from the front of the bridge to a suitabledistance beyond its rear, as shown at Fig. 1. The arching may besuitably supported by brickwork 17 located back of the bridge-wall andarranged to follow the contour of the flue.

The fifth course S may be formed of one or more slabs or quarries. Twoare shown in the drawings.

The transverse air passages S, 13, and 15 formed in both the third andfourth courses permit of the air freely circulating across the bridge,whereby it may become thoroughly warmed before mingling with theproducts of combustion at the rear of the bridge.

The mode of action is as follows :-The fuel is thrown on the grateeither by hand or mechanical stoker, and the air, besides beingdelivered out beyond the bridge with its passages in communication withthe passages I for secondary combustion, is also delivered in fan shapedcurrents from the passages E upward between the bars all over the gratesurface with a vertically upward motion through the grate which beingwell ventilated will not get so hot as would otherwise be the case, andthe adhering of clinker is entirely prevented. The air rises through thefuel vertically and the fiame strikes directly upward or nearly so,forming an intense flame bearing right against the crown of the furnaceand passing over the bridge with a considerable amount of carbonunconsumed. This flame meets the hot air ssuing through the bridge andthe remain- 1ng carbon hydrogen and other combustibles are at onceconsumed. The attendant in charge of the furnace can at any momentincrease or decrease the forced air current by regulating the steam jetsJ and thus the draft can be controlled to a nicety. The grate is wellsuited for burning small coal, coal dust, sawdust, and rubbish, andapplied to destructors and marine boilers is unequaled for economy andefficiency.

The air admitted to passages I and from under the firebars to thepassages and chambers formed in the various courses in the bridge ismade to take a zig-zag or tortuous course before it issues from the rearof the passageways 11 and 12 and conimingles with the gases and otherproducts of combustion that pass over the bridge and along the flue. Bythis means they become thoroughly heated before the mingling process isallowed to take place, whereby any cooling of the flue or gases thereinis prevented.

hat I claim as my invention, and desire to secure by Letters Patent, is

1. In a furnace having an ash pit, a grate formed of fire-bars providedwith openings therethrough extending the length of the grate, whereby topreheat the air passing therethrough, a bridge having a number ofchambers therein one above another and which communicate with oneanother out of line to form a tortuous passage, the lowermost of saidpassages being open at its base to the air passages in the grate of thefurnace and with its ash pit, and also having an opening near the top ofthe rear of the bridge, an arch extending from the front of the bridgeto a distance beyond the rear of the same, and supports for said archbeyond the bridge.

2. In a furnace having an ash pit, firebars provided with air conduitstherein, a bridge comprising courses horizontally disposed to formchambers therein one above the other, said chambers communicating witheach other out of line to form a tortuous passage open at its base tothe air passages in the fire-bars of the grate and. to the ash pit, andalso having an opening near the top of the rear of the bridge, supportson each side of the furnace beyond the bridge, and an arch extendingfrom the front of the bridge to a distance beyond its rear and supportedpartly by the bridge and partly by said supports.

3. In a furnace,a fire flue containing a grate formed of transversefire-bars provided with air conduits therein and having an ash pit belowthe fire-bars, a bridge comprising courses horizontally disposed to formchambers therein one above the other, said chambers communicating witheach other out of line to form a tortuous passage open at its base tothe air conduits in the fire-bars of the grate and to the ash pit, andalso having an opening near the top of the rear of the bridge, supportson each side of the furnace beyond the bridge and arranged to follow thecontour of the fine, and an arch ex tending from the front of the bridgeto a distance beyond its rear and supported partly by the bridge andpartly by said supports.

4. In a furnace, a grate composed of bars placed close together andhaving transverse openings therethrough forming a series of airconduits, a second series of air conduits through said bars intermediatethe first series, said second series terminating in up wardly disposedopenings in the rearmost of said bars, a bridge partially overlying thegrate and covering said openings and having formed therein a tortuouspassage communicating with said air conduits, and an air conductingpassage beneath the grate also communicating with said tortuous passage.

5. In a furnace, a grate composed of bars placed close together andhaving transverse openings therethrough forming a series of airconduits, a second series of air conduits through said bars intermediatethe first series, said second series terminating in upwardly disposedopenings in the rearmost of said bars, a bridge partially overlying thegrate and covering said openings and having formed therein a tortuousheating passage communicating with the said second series of airconduits in the bars and with an air conducting passage beneath thegrate, and provided above with an outlet for the heated air.

6. In a furnace, fire-bars provided with a series of air conduitstherein and having ducts leading therefrom, an ash pit, a bridge wallhaving an opening thereunder communicating with said ash pit, said airconduits leading to and closed by said bridge wall, said bridge wallcomprising a plurality of alternately disposed courses superposed andspaced to provide therein a tortuous air passage-way in communicationwith the opening thereunder, said fire-bars provided with a secondseries of air conduits intermediate said first-named series andcommunicating with the passageway in the bridge wall, supports on eitherside of said furnace beyond the bridge wall and an arch extending fromthe front of the bridge to a distance beyond its rear and upheld by saidbridge wall and supports.

7. In a furnace having an ash pit, firebars provided with aseries ofair-conduits therein, and having ducts leading therefrom, a bridge-wall,said air-conduits leading to and closed by said bridge-wall, saidbridge-wall comprising a plurality of alternately disposed coursessuperposed and 1 communicating With the ash-pit and the spaced toprovide a tortuous air passagetortuous passage-Way.

way, each of said courses comprising a In testimony whereof I havesigned my plurality of slabs, said fire-bars provided name to thisspecification'in the presence of 5 With a second series of air-conduitsintertWo subscribing Witnesses.

mediate said first named series, said second I j a q s 1 1 series oiconduits connnunlcating wlth the WALPER GEORGE OROSTHWAITE bridge-Wallpassage-way, and piers of brickitnesses:

Work on elther side of said furnace, said V. FAIRBURN-HART,

10 bridge-Wall having a passage-Way therein VVILLIAM SADLER.

